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Revision 1.64 by root, Fri Jun 6 11:01:17 2008 UTC vs.
Revision 1.108 by root, Tue Jan 6 20:08:05 2009 UTC

1package AnyEvent::Handle; 1package AnyEvent::Handle;
2 2
3no warnings; 3no warnings;
4use strict; 4use strict qw(subs vars);
5 5
6use AnyEvent (); 6use AnyEvent ();
7use AnyEvent::Util qw(WSAEWOULDBLOCK); 7use AnyEvent::Util qw(WSAEWOULDBLOCK);
8use Scalar::Util (); 8use Scalar::Util ();
9use Carp (); 9use Carp ();
14 14
15AnyEvent::Handle - non-blocking I/O on file handles via AnyEvent 15AnyEvent::Handle - non-blocking I/O on file handles via AnyEvent
16 16
17=cut 17=cut
18 18
19our $VERSION = 4.15; 19our $VERSION = 4.331;
20 20
21=head1 SYNOPSIS 21=head1 SYNOPSIS
22 22
23 use AnyEvent; 23 use AnyEvent;
24 use AnyEvent::Handle; 24 use AnyEvent::Handle;
27 27
28 my $handle = 28 my $handle =
29 AnyEvent::Handle->new ( 29 AnyEvent::Handle->new (
30 fh => \*STDIN, 30 fh => \*STDIN,
31 on_eof => sub { 31 on_eof => sub {
32 $cv->broadcast; 32 $cv->send;
33 }, 33 },
34 ); 34 );
35 35
36 # send some request line 36 # send some request line
37 $handle->push_write ("getinfo\015\012"); 37 $handle->push_write ("getinfo\015\012");
49 49
50This module is a helper module to make it easier to do event-based I/O on 50This module is a helper module to make it easier to do event-based I/O on
51filehandles. For utility functions for doing non-blocking connects and accepts 51filehandles. For utility functions for doing non-blocking connects and accepts
52on sockets see L<AnyEvent::Util>. 52on sockets see L<AnyEvent::Util>.
53 53
54The L<AnyEvent::Intro> tutorial contains some well-documented
55AnyEvent::Handle examples.
56
54In the following, when the documentation refers to of "bytes" then this 57In the following, when the documentation refers to of "bytes" then this
55means characters. As sysread and syswrite are used for all I/O, their 58means characters. As sysread and syswrite are used for all I/O, their
56treatment of characters applies to this module as well. 59treatment of characters applies to this module as well.
57 60
58All callbacks will be invoked with the handle object as their first 61All callbacks will be invoked with the handle object as their first
70 73
71=item fh => $filehandle [MANDATORY] 74=item fh => $filehandle [MANDATORY]
72 75
73The filehandle this L<AnyEvent::Handle> object will operate on. 76The filehandle this L<AnyEvent::Handle> object will operate on.
74 77
75NOTE: The filehandle will be set to non-blocking (using 78NOTE: The filehandle will be set to non-blocking mode (using
76AnyEvent::Util::fh_nonblocking). 79C<AnyEvent::Util::fh_nonblocking>) by the constructor and needs to stay in
80that mode.
77 81
78=item on_eof => $cb->($handle) 82=item on_eof => $cb->($handle)
79 83
80Set the callback to be called when an end-of-file condition is detcted, 84Set the callback to be called when an end-of-file condition is detected,
81i.e. in the case of a socket, when the other side has closed the 85i.e. in the case of a socket, when the other side has closed the
82connection cleanly. 86connection cleanly.
83 87
88For sockets, this just means that the other side has stopped sending data,
89you can still try to write data, and, in fact, one can return from the EOF
90callback and continue writing data, as only the read part has been shut
91down.
92
84While not mandatory, it is highly recommended to set an eof callback, 93While not mandatory, it is I<highly> recommended to set an EOF callback,
85otherwise you might end up with a closed socket while you are still 94otherwise you might end up with a closed socket while you are still
86waiting for data. 95waiting for data.
96
97If an EOF condition has been detected but no C<on_eof> callback has been
98set, then a fatal error will be raised with C<$!> set to <0>.
87 99
88=item on_error => $cb->($handle, $fatal) 100=item on_error => $cb->($handle, $fatal)
89 101
90This is the error callback, which is called when, well, some error 102This is the error callback, which is called when, well, some error
91occured, such as not being able to resolve the hostname, failure to 103occured, such as not being able to resolve the hostname, failure to
92connect or a read error. 104connect or a read error.
93 105
94Some errors are fatal (which is indicated by C<$fatal> being true). On 106Some errors are fatal (which is indicated by C<$fatal> being true). On
95fatal errors the handle object will be shut down and will not be 107fatal errors the handle object will be shut down and will not be usable
108(but you are free to look at the current C<< ->rbuf >>). Examples of fatal
109errors are an EOF condition with active (but unsatisifable) read watchers
110(C<EPIPE>) or I/O errors.
111
96usable. Non-fatal errors can be retried by simply returning, but it is 112Non-fatal errors can be retried by simply returning, but it is recommended
97recommended to simply ignore this parameter and instead abondon the handle 113to simply ignore this parameter and instead abondon the handle object
98object when this callback is invoked. 114when this callback is invoked. Examples of non-fatal errors are timeouts
115C<ETIMEDOUT>) or badly-formatted data (C<EBADMSG>).
99 116
100On callback entrance, the value of C<$!> contains the operating system 117On callback entrance, the value of C<$!> contains the operating system
101error (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT> or C<EBADMSG>). 118error (or C<ENOSPC>, C<EPIPE>, C<ETIMEDOUT> or C<EBADMSG>).
102 119
103While not mandatory, it is I<highly> recommended to set this callback, as 120While not mandatory, it is I<highly> recommended to set this callback, as
124This sets the callback that is called when the write buffer becomes empty 141This sets the callback that is called when the write buffer becomes empty
125(or when the callback is set and the buffer is empty already). 142(or when the callback is set and the buffer is empty already).
126 143
127To append to the write buffer, use the C<< ->push_write >> method. 144To append to the write buffer, use the C<< ->push_write >> method.
128 145
146This callback is useful when you don't want to put all of your write data
147into the queue at once, for example, when you want to write the contents
148of some file to the socket you might not want to read the whole file into
149memory and push it into the queue, but instead only read more data from
150the file when the write queue becomes empty.
151
129=item timeout => $fractional_seconds 152=item timeout => $fractional_seconds
130 153
131If non-zero, then this enables an "inactivity" timeout: whenever this many 154If non-zero, then this enables an "inactivity" timeout: whenever this many
132seconds pass without a successful read or write on the underlying file 155seconds pass without a successful read or write on the underlying file
133handle, the C<on_timeout> callback will be invoked (and if that one is 156handle, the C<on_timeout> callback will be invoked (and if that one is
134missing, an C<ETIMEDOUT> error will be raised). 157missing, a non-fatal C<ETIMEDOUT> error will be raised).
135 158
136Note that timeout processing is also active when you currently do not have 159Note that timeout processing is also active when you currently do not have
137any outstanding read or write requests: If you plan to keep the connection 160any outstanding read or write requests: If you plan to keep the connection
138idle then you should disable the timout temporarily or ignore the timeout 161idle then you should disable the timout temporarily or ignore the timeout
139in the C<on_timeout> callback. 162in the C<on_timeout> callback, in which case AnyEvent::Handle will simply
163restart the timeout.
140 164
141Zero (the default) disables this timeout. 165Zero (the default) disables this timeout.
142 166
143=item on_timeout => $cb->($handle) 167=item on_timeout => $cb->($handle)
144 168
148 172
149=item rbuf_max => <bytes> 173=item rbuf_max => <bytes>
150 174
151If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>) 175If defined, then a fatal error will be raised (with C<$!> set to C<ENOSPC>)
152when the read buffer ever (strictly) exceeds this size. This is useful to 176when the read buffer ever (strictly) exceeds this size. This is useful to
153avoid denial-of-service attacks. 177avoid some forms of denial-of-service attacks.
154 178
155For example, a server accepting connections from untrusted sources should 179For example, a server accepting connections from untrusted sources should
156be configured to accept only so-and-so much data that it cannot act on 180be configured to accept only so-and-so much data that it cannot act on
157(for example, when expecting a line, an attacker could send an unlimited 181(for example, when expecting a line, an attacker could send an unlimited
158amount of data without a callback ever being called as long as the line 182amount of data without a callback ever being called as long as the line
159isn't finished). 183isn't finished).
160 184
185=item autocork => <boolean>
186
187When disabled (the default), then C<push_write> will try to immediately
188write the data to the handle, if possible. This avoids having to register
189a write watcher and wait for the next event loop iteration, but can
190be inefficient if you write multiple small chunks (on the wire, this
191disadvantage is usually avoided by your kernel's nagle algorithm, see
192C<no_delay>, but this option can save costly syscalls).
193
194When enabled, then writes will always be queued till the next event loop
195iteration. This is efficient when you do many small writes per iteration,
196but less efficient when you do a single write only per iteration (or when
197the write buffer often is full). It also increases write latency.
198
199=item no_delay => <boolean>
200
201When doing small writes on sockets, your operating system kernel might
202wait a bit for more data before actually sending it out. This is called
203the Nagle algorithm, and usually it is beneficial.
204
205In some situations you want as low a delay as possible, which can be
206accomplishd by setting this option to a true value.
207
208The default is your opertaing system's default behaviour (most likely
209enabled), this option explicitly enables or disables it, if possible.
210
161=item read_size => <bytes> 211=item read_size => <bytes>
162 212
163The default read block size (the amount of bytes this module will try to read 213The default read block size (the amount of bytes this module will
164during each (loop iteration). Default: C<8192>. 214try to read during each loop iteration, which affects memory
215requirements). Default: C<8192>.
165 216
166=item low_water_mark => <bytes> 217=item low_water_mark => <bytes>
167 218
168Sets the amount of bytes (default: C<0>) that make up an "empty" write 219Sets the amount of bytes (default: C<0>) that make up an "empty" write
169buffer: If the write reaches this size or gets even samller it is 220buffer: If the write reaches this size or gets even samller it is
170considered empty. 221considered empty.
171 222
223Sometimes it can be beneficial (for performance reasons) to add data to
224the write buffer before it is fully drained, but this is a rare case, as
225the operating system kernel usually buffers data as well, so the default
226is good in almost all cases.
227
172=item linger => <seconds> 228=item linger => <seconds>
173 229
174If non-zero (default: C<3600>), then the destructor of the 230If non-zero (default: C<3600>), then the destructor of the
175AnyEvent::Handle object will check wether there is still outstanding write 231AnyEvent::Handle object will check whether there is still outstanding
176data and will install a watcher that will write out this data. No errors 232write data and will install a watcher that will write this data to the
177will be reported (this mostly matches how the operating system treats 233socket. No errors will be reported (this mostly matches how the operating
178outstanding data at socket close time). 234system treats outstanding data at socket close time).
179 235
180This will not work for partial TLS data that could not yet been 236This will not work for partial TLS data that could not be encoded
181encoded. This data will be lost. 237yet. This data will be lost. Calling the C<stoptls> method in time might
238help.
182 239
183=item tls => "accept" | "connect" | Net::SSLeay::SSL object 240=item tls => "accept" | "connect" | Net::SSLeay::SSL object
184 241
185When this parameter is given, it enables TLS (SSL) mode, that means it 242When this parameter is given, it enables TLS (SSL) mode, that means
186will start making tls handshake and will transparently encrypt/decrypt 243AnyEvent will start a TLS handshake as soon as the conenction has been
187data. 244established and will transparently encrypt/decrypt data afterwards.
188 245
189TLS mode requires Net::SSLeay to be installed (it will be loaded 246TLS mode requires Net::SSLeay to be installed (it will be loaded
190automatically when you try to create a TLS handle). 247automatically when you try to create a TLS handle): this module doesn't
248have a dependency on that module, so if your module requires it, you have
249to add the dependency yourself.
191 250
192For the TLS server side, use C<accept>, and for the TLS client side of a 251Unlike TCP, TLS has a server and client side: for the TLS server side, use
193connection, use C<connect> mode. 252C<accept>, and for the TLS client side of a connection, use C<connect>
253mode.
194 254
195You can also provide your own TLS connection object, but you have 255You can also provide your own TLS connection object, but you have
196to make sure that you call either C<Net::SSLeay::set_connect_state> 256to make sure that you call either C<Net::SSLeay::set_connect_state>
197or C<Net::SSLeay::set_accept_state> on it before you pass it to 257or C<Net::SSLeay::set_accept_state> on it before you pass it to
198AnyEvent::Handle. 258AnyEvent::Handle.
199 259
200See the C<starttls> method if you need to start TLs negotiation later. 260See the C<< ->starttls >> method for when need to start TLS negotiation later.
201 261
202=item tls_ctx => $ssl_ctx 262=item tls_ctx => $ssl_ctx
203 263
204Use the given Net::SSLeay::CTX object to create the new TLS connection 264Use the given C<Net::SSLeay::CTX> object to create the new TLS connection
205(unless a connection object was specified directly). If this parameter is 265(unless a connection object was specified directly). If this parameter is
206missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>. 266missing, then AnyEvent::Handle will use C<AnyEvent::Handle::TLS_CTX>.
207 267
208=item json => JSON or JSON::XS object 268=item json => JSON or JSON::XS object
209 269
210This is the json coder object used by the C<json> read and write types. 270This is the json coder object used by the C<json> read and write types.
211 271
212If you don't supply it, then AnyEvent::Handle will create and use a 272If you don't supply it, then AnyEvent::Handle will create and use a
213suitable one, which will write and expect UTF-8 encoded JSON texts. 273suitable one (on demand), which will write and expect UTF-8 encoded JSON
274texts.
214 275
215Note that you are responsible to depend on the JSON module if you want to 276Note that you are responsible to depend on the JSON module if you want to
216use this functionality, as AnyEvent does not have a dependency itself. 277use this functionality, as AnyEvent does not have a dependency itself.
217 278
218=item filter_r => $cb
219
220=item filter_w => $cb
221
222These exist, but are undocumented at this time.
223
224=back 279=back
225 280
226=cut 281=cut
227 282
228sub new { 283sub new {
232 287
233 $self->{fh} or Carp::croak "mandatory argument fh is missing"; 288 $self->{fh} or Carp::croak "mandatory argument fh is missing";
234 289
235 AnyEvent::Util::fh_nonblocking $self->{fh}, 1; 290 AnyEvent::Util::fh_nonblocking $self->{fh}, 1;
236 291
237 if ($self->{tls}) {
238 require Net::SSLeay;
239 $self->starttls (delete $self->{tls}, delete $self->{tls_ctx}); 292 $self->starttls (delete $self->{tls}, delete $self->{tls_ctx})
240 } 293 if $self->{tls};
241 294
242 $self->{_activity} = AnyEvent->now; 295 $self->{_activity} = AnyEvent->now;
243 $self->_timeout; 296 $self->_timeout;
244 297
245 $self->on_drain (delete $self->{on_drain}) if $self->{on_drain}; 298 $self->on_drain (delete $self->{on_drain}) if exists $self->{on_drain};
299 $self->no_delay (delete $self->{no_delay}) if exists $self->{no_delay};
300
301 $self->start_read
302 if $self->{on_read};
246 303
247 $self 304 $self
248} 305}
249 306
250sub _shutdown { 307sub _shutdown {
253 delete $self->{_tw}; 310 delete $self->{_tw};
254 delete $self->{_rw}; 311 delete $self->{_rw};
255 delete $self->{_ww}; 312 delete $self->{_ww};
256 delete $self->{fh}; 313 delete $self->{fh};
257 314
258 $self->stoptls; 315 &_freetls;
316
317 delete $self->{on_read};
318 delete $self->{_queue};
259} 319}
260 320
261sub _error { 321sub _error {
262 my ($self, $errno, $fatal) = @_; 322 my ($self, $errno, $fatal) = @_;
263 323
266 326
267 $! = $errno; 327 $! = $errno;
268 328
269 if ($self->{on_error}) { 329 if ($self->{on_error}) {
270 $self->{on_error}($self, $fatal); 330 $self->{on_error}($self, $fatal);
271 } else { 331 } elsif ($self->{fh}) {
272 Carp::croak "AnyEvent::Handle uncaught error: $!"; 332 Carp::croak "AnyEvent::Handle uncaught error: $!";
273 } 333 }
274} 334}
275 335
276=item $fh = $handle->fh 336=item $fh = $handle->fh
277 337
278This method returns the file handle of the L<AnyEvent::Handle> object. 338This method returns the file handle used to create the L<AnyEvent::Handle> object.
279 339
280=cut 340=cut
281 341
282sub fh { $_[0]{fh} } 342sub fh { $_[0]{fh} }
283 343
301 $_[0]{on_eof} = $_[1]; 361 $_[0]{on_eof} = $_[1];
302} 362}
303 363
304=item $handle->on_timeout ($cb) 364=item $handle->on_timeout ($cb)
305 365
306Replace the current C<on_timeout> callback, or disables the callback 366Replace the current C<on_timeout> callback, or disables the callback (but
307(but not the timeout) if C<$cb> = C<undef>. See C<timeout> constructor 367not the timeout) if C<$cb> = C<undef>. See the C<timeout> constructor
308argument. 368argument and method.
309 369
310=cut 370=cut
311 371
312sub on_timeout { 372sub on_timeout {
313 $_[0]{on_timeout} = $_[1]; 373 $_[0]{on_timeout} = $_[1];
374}
375
376=item $handle->autocork ($boolean)
377
378Enables or disables the current autocork behaviour (see C<autocork>
379constructor argument). Changes will only take effect on the next write.
380
381=cut
382
383sub autocork {
384 $_[0]{autocork} = $_[1];
385}
386
387=item $handle->no_delay ($boolean)
388
389Enables or disables the C<no_delay> setting (see constructor argument of
390the same name for details).
391
392=cut
393
394sub no_delay {
395 $_[0]{no_delay} = $_[1];
396
397 eval {
398 local $SIG{__DIE__};
399 setsockopt $_[0]{fh}, &Socket::IPPROTO_TCP, &Socket::TCP_NODELAY, int $_[1];
400 };
314} 401}
315 402
316############################################################################# 403#############################################################################
317 404
318=item $handle->timeout ($seconds) 405=item $handle->timeout ($seconds)
396 my ($self, $cb) = @_; 483 my ($self, $cb) = @_;
397 484
398 $self->{on_drain} = $cb; 485 $self->{on_drain} = $cb;
399 486
400 $cb->($self) 487 $cb->($self)
401 if $cb && $self->{low_water_mark} >= length $self->{wbuf}; 488 if $cb && $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf});
402} 489}
403 490
404=item $handle->push_write ($data) 491=item $handle->push_write ($data)
405 492
406Queues the given scalar to be written. You can push as much data as you 493Queues the given scalar to be written. You can push as much data as you
423 substr $self->{wbuf}, 0, $len, ""; 510 substr $self->{wbuf}, 0, $len, "";
424 511
425 $self->{_activity} = AnyEvent->now; 512 $self->{_activity} = AnyEvent->now;
426 513
427 $self->{on_drain}($self) 514 $self->{on_drain}($self)
428 if $self->{low_water_mark} >= length $self->{wbuf} 515 if $self->{low_water_mark} >= (length $self->{wbuf}) + (length $self->{_tls_wbuf})
429 && $self->{on_drain}; 516 && $self->{on_drain};
430 517
431 delete $self->{_ww} unless length $self->{wbuf}; 518 delete $self->{_ww} unless length $self->{wbuf};
432 } elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) { 519 } elsif ($! != EAGAIN && $! != EINTR && $! != WSAEWOULDBLOCK) {
433 $self->_error ($!, 1); 520 $self->_error ($!, 1);
434 } 521 }
435 }; 522 };
436 523
437 # try to write data immediately 524 # try to write data immediately
438 $cb->(); 525 $cb->() unless $self->{autocork};
439 526
440 # if still data left in wbuf, we need to poll 527 # if still data left in wbuf, we need to poll
441 $self->{_ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb) 528 $self->{_ww} = AnyEvent->io (fh => $self->{fh}, poll => "w", cb => $cb)
442 if length $self->{wbuf}; 529 if length $self->{wbuf};
443 }; 530 };
457 544
458 @_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write") 545 @_ = ($WH{$type} or Carp::croak "unsupported type passed to AnyEvent::Handle::push_write")
459 ->($self, @_); 546 ->($self, @_);
460 } 547 }
461 548
462 if ($self->{filter_w}) { 549 if ($self->{tls}) {
463 $self->{filter_w}($self, \$_[0]); 550 $self->{_tls_wbuf} .= $_[0];
551
552 &_dotls ($self);
464 } else { 553 } else {
465 $self->{wbuf} .= $_[0]; 554 $self->{wbuf} .= $_[0];
466 $self->_drain_wbuf; 555 $self->_drain_wbuf;
467 } 556 }
468} 557}
485=cut 574=cut
486 575
487register_write_type netstring => sub { 576register_write_type netstring => sub {
488 my ($self, $string) = @_; 577 my ($self, $string) = @_;
489 578
490 sprintf "%d:%s,", (length $string), $string 579 (length $string) . ":$string,"
491}; 580};
492 581
493=item packstring => $format, $data 582=item packstring => $format, $data
494 583
495An octet string prefixed with an encoded length. The encoding C<$format> 584An octet string prefixed with an encoded length. The encoding C<$format>
500=cut 589=cut
501 590
502register_write_type packstring => sub { 591register_write_type packstring => sub {
503 my ($self, $format, $string) = @_; 592 my ($self, $format, $string) = @_;
504 593
505 pack "$format/a", $string 594 pack "$format/a*", $string
506}; 595};
507 596
508=item json => $array_or_hashref 597=item json => $array_or_hashref
509 598
510Encodes the given hash or array reference into a JSON object. Unless you 599Encodes the given hash or array reference into a JSON object. Unless you
556register_write_type storable => sub { 645register_write_type storable => sub {
557 my ($self, $ref) = @_; 646 my ($self, $ref) = @_;
558 647
559 require Storable; 648 require Storable;
560 649
561 pack "w/a", Storable::nfreeze ($ref) 650 pack "w/a*", Storable::nfreeze ($ref)
562}; 651};
563 652
564=back 653=back
565 654
566=item AnyEvent::Handle::register_write_type type => $coderef->($handle, @args) 655=item AnyEvent::Handle::register_write_type type => $coderef->($handle, @args)
590ways, the "simple" way, using only C<on_read> and the "complex" way, using 679ways, the "simple" way, using only C<on_read> and the "complex" way, using
591a queue. 680a queue.
592 681
593In the simple case, you just install an C<on_read> callback and whenever 682In the simple case, you just install an C<on_read> callback and whenever
594new data arrives, it will be called. You can then remove some data (if 683new data arrives, it will be called. You can then remove some data (if
595enough is there) from the read buffer (C<< $handle->rbuf >>) if you want 684enough is there) from the read buffer (C<< $handle->rbuf >>). Or you cna
596or not. 685leave the data there if you want to accumulate more (e.g. when only a
686partial message has been received so far).
597 687
598In the more complex case, you want to queue multiple callbacks. In this 688In the more complex case, you want to queue multiple callbacks. In this
599case, AnyEvent::Handle will call the first queued callback each time new 689case, AnyEvent::Handle will call the first queued callback each time new
600data arrives (also the first time it is queued) and removes it when it has 690data arrives (also the first time it is queued) and removes it when it has
601done its job (see C<push_read>, below). 691done its job (see C<push_read>, below).
619 # handle xml 709 # handle xml
620 }); 710 });
621 }); 711 });
622 }); 712 });
623 713
624Example 2: Implement a client for a protocol that replies either with 714Example 2: Implement a client for a protocol that replies either with "OK"
625"OK" and another line or "ERROR" for one request, and 64 bytes for the 715and another line or "ERROR" for the first request that is sent, and 64
626second request. Due tot he availability of a full queue, we can just 716bytes for the second request. Due to the availability of a queue, we can
627pipeline sending both requests and manipulate the queue as necessary in 717just pipeline sending both requests and manipulate the queue as necessary
628the callbacks: 718in the callbacks.
629 719
630 # request one 720When the first callback is called and sees an "OK" response, it will
721C<unshift> another line-read. This line-read will be queued I<before> the
72264-byte chunk callback.
723
724 # request one, returns either "OK + extra line" or "ERROR"
631 $handle->push_write ("request 1\015\012"); 725 $handle->push_write ("request 1\015\012");
632 726
633 # we expect "ERROR" or "OK" as response, so push a line read 727 # we expect "ERROR" or "OK" as response, so push a line read
634 $handle->push_read (line => sub { 728 $handle->push_read (line => sub {
635 # if we got an "OK", we have to _prepend_ another line, 729 # if we got an "OK", we have to _prepend_ another line,
642 ... 736 ...
643 }); 737 });
644 } 738 }
645 }); 739 });
646 740
647 # request two 741 # request two, simply returns 64 octets
648 $handle->push_write ("request 2\015\012"); 742 $handle->push_write ("request 2\015\012");
649 743
650 # simply read 64 bytes, always 744 # simply read 64 bytes, always
651 $handle->push_read (chunk => 64, sub { 745 $handle->push_read (chunk => 64, sub {
652 my $response = $_[1]; 746 my $response = $_[1];
664 758
665 if ( 759 if (
666 defined $self->{rbuf_max} 760 defined $self->{rbuf_max}
667 && $self->{rbuf_max} < length $self->{rbuf} 761 && $self->{rbuf_max} < length $self->{rbuf}
668 ) { 762 ) {
669 return $self->_error (&Errno::ENOSPC, 1); 763 $self->_error (&Errno::ENOSPC, 1), return;
670 } 764 }
671 765
672 while () { 766 while () {
673 no strict 'refs';
674
675 my $len = length $self->{rbuf}; 767 my $len = length $self->{rbuf};
676 768
677 if (my $cb = shift @{ $self->{_queue} }) { 769 if (my $cb = shift @{ $self->{_queue} }) {
678 unless ($cb->($self)) { 770 unless ($cb->($self)) {
679 if ($self->{_eof}) { 771 if ($self->{_eof}) {
680 # no progress can be made (not enough data and no data forthcoming) 772 # no progress can be made (not enough data and no data forthcoming)
681 $self->_error (&Errno::EPIPE, 1), last; 773 $self->_error (&Errno::EPIPE, 1), return;
682 } 774 }
683 775
684 unshift @{ $self->{_queue} }, $cb; 776 unshift @{ $self->{_queue} }, $cb;
685 last; 777 last;
686 } 778 }
694 && !@{ $self->{_queue} } # and the queue is still empty 786 && !@{ $self->{_queue} } # and the queue is still empty
695 && $self->{on_read} # but we still have on_read 787 && $self->{on_read} # but we still have on_read
696 ) { 788 ) {
697 # no further data will arrive 789 # no further data will arrive
698 # so no progress can be made 790 # so no progress can be made
699 $self->_error (&Errno::EPIPE, 1), last 791 $self->_error (&Errno::EPIPE, 1), return
700 if $self->{_eof}; 792 if $self->{_eof};
701 793
702 last; # more data might arrive 794 last; # more data might arrive
703 } 795 }
704 } else { 796 } else {
705 # read side becomes idle 797 # read side becomes idle
706 delete $self->{_rw}; 798 delete $self->{_rw} unless $self->{tls};
707 last; 799 last;
708 } 800 }
709 } 801 }
710 802
803 if ($self->{_eof}) {
804 if ($self->{on_eof}) {
711 $self->{on_eof}($self) 805 $self->{on_eof}($self)
712 if $self->{_eof} && $self->{on_eof}; 806 } else {
807 $self->_error (0, 1);
808 }
809 }
713 810
714 # may need to restart read watcher 811 # may need to restart read watcher
715 unless ($self->{_rw}) { 812 unless ($self->{_rw}) {
716 $self->start_read 813 $self->start_read
717 if $self->{on_read} || @{ $self->{_queue} }; 814 if $self->{on_read} || @{ $self->{_queue} };
843 $cb->($_[0], substr $_[0]{rbuf}, 0, $len, ""); 940 $cb->($_[0], substr $_[0]{rbuf}, 0, $len, "");
844 1 941 1
845 } 942 }
846}; 943};
847 944
848# compatibility with older API
849sub push_read_chunk {
850 $_[0]->push_read (chunk => $_[1], $_[2]);
851}
852
853sub unshift_read_chunk {
854 $_[0]->unshift_read (chunk => $_[1], $_[2]);
855}
856
857=item line => [$eol, ]$cb->($handle, $line, $eol) 945=item line => [$eol, ]$cb->($handle, $line, $eol)
858 946
859The callback will be called only once a full line (including the end of 947The callback will be called only once a full line (including the end of
860line marker, C<$eol>) has been read. This line (excluding the end of line 948line marker, C<$eol>) has been read. This line (excluding the end of line
861marker) will be passed to the callback as second argument (C<$line>), and 949marker) will be passed to the callback as second argument (C<$line>), and
876=cut 964=cut
877 965
878register_read_type line => sub { 966register_read_type line => sub {
879 my ($self, $cb, $eol) = @_; 967 my ($self, $cb, $eol) = @_;
880 968
881 $eol = qr|(\015?\012)| if @_ < 3; 969 if (@_ < 3) {
970 # this is more than twice as fast as the generic code below
971 sub {
972 $_[0]{rbuf} =~ s/^([^\015\012]*)(\015?\012)// or return;
973
974 $cb->($_[0], $1, $2);
975 1
976 }
977 } else {
882 $eol = quotemeta $eol unless ref $eol; 978 $eol = quotemeta $eol unless ref $eol;
883 $eol = qr|^(.*?)($eol)|s; 979 $eol = qr|^(.*?)($eol)|s;
884 980
885 sub { 981 sub {
886 $_[0]{rbuf} =~ s/$eol// or return; 982 $_[0]{rbuf} =~ s/$eol// or return;
887 983
888 $cb->($_[0], $1, $2); 984 $cb->($_[0], $1, $2);
985 1
889 1 986 }
890 } 987 }
891}; 988};
892
893# compatibility with older API
894sub push_read_line {
895 my $self = shift;
896 $self->push_read (line => @_);
897}
898
899sub unshift_read_line {
900 my $self = shift;
901 $self->unshift_read (line => @_);
902}
903 989
904=item regex => $accept[, $reject[, $skip], $cb->($handle, $data) 990=item regex => $accept[, $reject[, $skip], $cb->($handle, $data)
905 991
906Makes a regex match against the regex object C<$accept> and returns 992Makes a regex match against the regex object C<$accept> and returns
907everything up to and including the match. 993everything up to and including the match.
1012An octet string prefixed with an encoded length. The encoding C<$format> 1098An octet string prefixed with an encoded length. The encoding C<$format>
1013uses the same format as a Perl C<pack> format, but must specify a single 1099uses the same format as a Perl C<pack> format, but must specify a single
1014integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an 1100integer only (only one of C<cCsSlLqQiInNvVjJw> is allowed, plus an
1015optional C<!>, C<< < >> or C<< > >> modifier). 1101optional C<!>, C<< < >> or C<< > >> modifier).
1016 1102
1017DNS over TCP uses a prefix of C<n>, EPP uses a prefix of C<N>. 1103For example, DNS over TCP uses a prefix of C<n> (2 octet network order),
1104EPP uses a prefix of C<N> (4 octtes).
1018 1105
1019Example: read a block of data prefixed by its length in BER-encoded 1106Example: read a block of data prefixed by its length in BER-encoded
1020format (very efficient). 1107format (very efficient).
1021 1108
1022 $handle->push_read (packstring => "w", sub { 1109 $handle->push_read (packstring => "w", sub {
1028register_read_type packstring => sub { 1115register_read_type packstring => sub {
1029 my ($self, $cb, $format) = @_; 1116 my ($self, $cb, $format) = @_;
1030 1117
1031 sub { 1118 sub {
1032 # when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method 1119 # when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
1033 defined (my $len = eval { unpack $format, $_[0]->{rbuf} }) 1120 defined (my $len = eval { unpack $format, $_[0]{rbuf} })
1034 or return; 1121 or return;
1035 1122
1123 $format = length pack $format, $len;
1124
1125 # bypass unshift if we already have the remaining chunk
1126 if ($format + $len <= length $_[0]{rbuf}) {
1127 my $data = substr $_[0]{rbuf}, $format, $len;
1128 substr $_[0]{rbuf}, 0, $format + $len, "";
1129 $cb->($_[0], $data);
1130 } else {
1036 # remove prefix 1131 # remove prefix
1037 substr $_[0]->{rbuf}, 0, (length pack $format, $len), ""; 1132 substr $_[0]{rbuf}, 0, $format, "";
1038 1133
1039 # read rest 1134 # read remaining chunk
1040 $_[0]->unshift_read (chunk => $len, $cb); 1135 $_[0]->unshift_read (chunk => $len, $cb);
1136 }
1041 1137
1042 1 1138 1
1043 } 1139 }
1044}; 1140};
1045 1141
1102 1198
1103 require Storable; 1199 require Storable;
1104 1200
1105 sub { 1201 sub {
1106 # when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method 1202 # when we can use 5.10 we can use ".", but for 5.8 we use the re-pack method
1107 defined (my $len = eval { unpack "w", $_[0]->{rbuf} }) 1203 defined (my $len = eval { unpack "w", $_[0]{rbuf} })
1108 or return; 1204 or return;
1109 1205
1206 my $format = length pack "w", $len;
1207
1208 # bypass unshift if we already have the remaining chunk
1209 if ($format + $len <= length $_[0]{rbuf}) {
1210 my $data = substr $_[0]{rbuf}, $format, $len;
1211 substr $_[0]{rbuf}, 0, $format + $len, "";
1212 $cb->($_[0], Storable::thaw ($data));
1213 } else {
1110 # remove prefix 1214 # remove prefix
1111 substr $_[0]->{rbuf}, 0, (length pack "w", $len), ""; 1215 substr $_[0]{rbuf}, 0, $format, "";
1112 1216
1113 # read rest 1217 # read remaining chunk
1114 $_[0]->unshift_read (chunk => $len, sub { 1218 $_[0]->unshift_read (chunk => $len, sub {
1115 if (my $ref = eval { Storable::thaw ($_[1]) }) { 1219 if (my $ref = eval { Storable::thaw ($_[1]) }) {
1116 $cb->($_[0], $ref); 1220 $cb->($_[0], $ref);
1117 } else { 1221 } else {
1118 $self->_error (&Errno::EBADMSG); 1222 $self->_error (&Errno::EBADMSG);
1223 }
1119 } 1224 });
1120 }); 1225 }
1226
1227 1
1121 } 1228 }
1122}; 1229};
1123 1230
1124=back 1231=back
1125 1232
1155Note that AnyEvent::Handle will automatically C<start_read> for you when 1262Note that AnyEvent::Handle will automatically C<start_read> for you when
1156you change the C<on_read> callback or push/unshift a read callback, and it 1263you change the C<on_read> callback or push/unshift a read callback, and it
1157will automatically C<stop_read> for you when neither C<on_read> is set nor 1264will automatically C<stop_read> for you when neither C<on_read> is set nor
1158there are any read requests in the queue. 1265there are any read requests in the queue.
1159 1266
1267These methods will have no effect when in TLS mode (as TLS doesn't support
1268half-duplex connections).
1269
1160=cut 1270=cut
1161 1271
1162sub stop_read { 1272sub stop_read {
1163 my ($self) = @_; 1273 my ($self) = @_;
1164 1274
1165 delete $self->{_rw}; 1275 delete $self->{_rw} unless $self->{tls};
1166} 1276}
1167 1277
1168sub start_read { 1278sub start_read {
1169 my ($self) = @_; 1279 my ($self) = @_;
1170 1280
1171 unless ($self->{_rw} || $self->{_eof}) { 1281 unless ($self->{_rw} || $self->{_eof}) {
1172 Scalar::Util::weaken $self; 1282 Scalar::Util::weaken $self;
1173 1283
1174 $self->{_rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub { 1284 $self->{_rw} = AnyEvent->io (fh => $self->{fh}, poll => "r", cb => sub {
1175 my $rbuf = $self->{filter_r} ? \my $buf : \$self->{rbuf}; 1285 my $rbuf = \($self->{tls} ? my $buf : $self->{rbuf});
1176 my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf; 1286 my $len = sysread $self->{fh}, $$rbuf, $self->{read_size} || 8192, length $$rbuf;
1177 1287
1178 if ($len > 0) { 1288 if ($len > 0) {
1179 $self->{_activity} = AnyEvent->now; 1289 $self->{_activity} = AnyEvent->now;
1180 1290
1181 $self->{filter_r} 1291 if ($self->{tls}) {
1182 ? $self->{filter_r}($self, $rbuf) 1292 Net::SSLeay::BIO_write ($self->{_rbio}, $$rbuf);
1183 : $self->{_in_drain} || $self->_drain_rbuf; 1293
1294 &_dotls ($self);
1295 } else {
1296 $self->_drain_rbuf unless $self->{_in_drain};
1297 }
1184 1298
1185 } elsif (defined $len) { 1299 } elsif (defined $len) {
1186 delete $self->{_rw}; 1300 delete $self->{_rw};
1187 $self->{_eof} = 1; 1301 $self->{_eof} = 1;
1188 $self->_drain_rbuf unless $self->{_in_drain}; 1302 $self->_drain_rbuf unless $self->{_in_drain};
1192 } 1306 }
1193 }); 1307 });
1194 } 1308 }
1195} 1309}
1196 1310
1311# poll the write BIO and send the data if applicable
1197sub _dotls { 1312sub _dotls {
1198 my ($self) = @_; 1313 my ($self) = @_;
1199 1314
1200 my $buf; 1315 my $tmp;
1201 1316
1202 if (length $self->{_tls_wbuf}) { 1317 if (length $self->{_tls_wbuf}) {
1203 while ((my $len = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) { 1318 while (($tmp = Net::SSLeay::write ($self->{tls}, $self->{_tls_wbuf})) > 0) {
1204 substr $self->{_tls_wbuf}, 0, $len, ""; 1319 substr $self->{_tls_wbuf}, 0, $tmp, "";
1205 } 1320 }
1206 } 1321 }
1207 1322
1208 if (length ($buf = Net::SSLeay::BIO_read ($self->{_wbio}))) {
1209 $self->{wbuf} .= $buf;
1210 $self->_drain_wbuf;
1211 }
1212
1213 while (defined ($buf = Net::SSLeay::read ($self->{tls}))) { 1323 while (defined ($tmp = Net::SSLeay::read ($self->{tls}))) {
1214 if (length $buf) { 1324 unless (length $tmp) {
1215 $self->{rbuf} .= $buf;
1216 $self->_drain_rbuf unless $self->{_in_drain};
1217 } else {
1218 # let's treat SSL-eof as we treat normal EOF 1325 # let's treat SSL-eof as we treat normal EOF
1326 delete $self->{_rw};
1219 $self->{_eof} = 1; 1327 $self->{_eof} = 1;
1220 $self->_shutdown; 1328 &_freetls;
1221 return;
1222 } 1329 }
1223 }
1224 1330
1331 $self->{rbuf} .= $tmp;
1332 $self->_drain_rbuf unless $self->{_in_drain};
1333 $self->{tls} or return; # tls session might have gone away in callback
1334 }
1335
1225 my $err = Net::SSLeay::get_error ($self->{tls}, -1); 1336 $tmp = Net::SSLeay::get_error ($self->{tls}, -1);
1226 1337
1227 if ($err!= Net::SSLeay::ERROR_WANT_READ ()) { 1338 if ($tmp != Net::SSLeay::ERROR_WANT_READ ()) {
1228 if ($err == Net::SSLeay::ERROR_SYSCALL ()) { 1339 if ($tmp == Net::SSLeay::ERROR_SYSCALL ()) {
1229 return $self->_error ($!, 1); 1340 return $self->_error ($!, 1);
1230 } elsif ($err == Net::SSLeay::ERROR_SSL ()) { 1341 } elsif ($tmp == Net::SSLeay::ERROR_SSL ()) {
1231 return $self->_error (&Errno::EIO, 1); 1342 return $self->_error (&Errno::EIO, 1);
1232 } 1343 }
1233 1344
1234 # all others are fine for our purposes 1345 # all other errors are fine for our purposes
1346 }
1347
1348 while (length ($tmp = Net::SSLeay::BIO_read ($self->{_wbio}))) {
1349 $self->{wbuf} .= $tmp;
1350 $self->_drain_wbuf;
1235 } 1351 }
1236} 1352}
1237 1353
1238=item $handle->starttls ($tls[, $tls_ctx]) 1354=item $handle->starttls ($tls[, $tls_ctx])
1239 1355
1249 1365
1250The TLS connection object will end up in C<< $handle->{tls} >> after this 1366The TLS connection object will end up in C<< $handle->{tls} >> after this
1251call and can be used or changed to your liking. Note that the handshake 1367call and can be used or changed to your liking. Note that the handshake
1252might have already started when this function returns. 1368might have already started when this function returns.
1253 1369
1370If it an error to start a TLS handshake more than once per
1371AnyEvent::Handle object (this is due to bugs in OpenSSL).
1372
1254=cut 1373=cut
1255 1374
1256sub starttls { 1375sub starttls {
1257 my ($self, $ssl, $ctx) = @_; 1376 my ($self, $ssl, $ctx) = @_;
1258 1377
1259 $self->stoptls; 1378 require Net::SSLeay;
1260 1379
1380 Carp::croak "it is an error to call starttls more than once on an AnyEvent::Handle object"
1381 if $self->{tls};
1382
1261 if ($ssl eq "accept") { 1383 if ($ssl eq "accept") {
1262 $ssl = Net::SSLeay::new ($ctx || TLS_CTX ()); 1384 $ssl = Net::SSLeay::new ($ctx || TLS_CTX ());
1263 Net::SSLeay::set_accept_state ($ssl); 1385 Net::SSLeay::set_accept_state ($ssl);
1264 } elsif ($ssl eq "connect") { 1386 } elsif ($ssl eq "connect") {
1265 $ssl = Net::SSLeay::new ($ctx || TLS_CTX ()); 1387 $ssl = Net::SSLeay::new ($ctx || TLS_CTX ());
1271 # basically, this is deep magic (because SSL_read should have the same issues) 1393 # basically, this is deep magic (because SSL_read should have the same issues)
1272 # but the openssl maintainers basically said: "trust us, it just works". 1394 # but the openssl maintainers basically said: "trust us, it just works".
1273 # (unfortunately, we have to hardcode constants because the abysmally misdesigned 1395 # (unfortunately, we have to hardcode constants because the abysmally misdesigned
1274 # and mismaintained ssleay-module doesn't even offer them). 1396 # and mismaintained ssleay-module doesn't even offer them).
1275 # http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html 1397 # http://www.mail-archive.com/openssl-dev@openssl.org/msg22420.html
1398 #
1399 # in short: this is a mess.
1400 #
1401 # note that we do not try to keep the length constant between writes as we are required to do.
1402 # we assume that most (but not all) of this insanity only applies to non-blocking cases,
1403 # and we drive openssl fully in blocking mode here. Or maybe we don't - openssl seems to
1404 # have identity issues in that area.
1276 Net::SSLeay::CTX_set_mode ($self->{tls}, 1405 Net::SSLeay::CTX_set_mode ($self->{tls},
1277 (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1) 1406 (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ENABLE_PARTIAL_WRITE () } || 1)
1278 | (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2)); 1407 | (eval { local $SIG{__DIE__}; Net::SSLeay::MODE_ACCEPT_MOVING_WRITE_BUFFER () } || 2));
1279 1408
1280 $self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ()); 1409 $self->{_rbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
1281 $self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ()); 1410 $self->{_wbio} = Net::SSLeay::BIO_new (Net::SSLeay::BIO_s_mem ());
1282 1411
1283 Net::SSLeay::set_bio ($ssl, $self->{_rbio}, $self->{_wbio}); 1412 Net::SSLeay::set_bio ($ssl, $self->{_rbio}, $self->{_wbio});
1284 1413
1285 $self->{filter_w} = sub { 1414 &_dotls; # need to trigger the initial handshake
1286 $_[0]{_tls_wbuf} .= ${$_[1]}; 1415 $self->start_read; # make sure we actually do read
1287 &_dotls;
1288 };
1289 $self->{filter_r} = sub {
1290 Net::SSLeay::BIO_write ($_[0]{_rbio}, ${$_[1]});
1291 &_dotls;
1292 };
1293} 1416}
1294 1417
1295=item $handle->stoptls 1418=item $handle->stoptls
1296 1419
1297Destroys the SSL connection, if any. Partial read or write data will be 1420Shuts down the SSL connection - this makes a proper EOF handshake by
1298lost. 1421sending a close notify to the other side, but since OpenSSL doesn't
1422support non-blocking shut downs, it is not possible to re-use the stream
1423afterwards.
1299 1424
1300=cut 1425=cut
1301 1426
1302sub stoptls { 1427sub stoptls {
1303 my ($self) = @_; 1428 my ($self) = @_;
1304 1429
1430 if ($self->{tls}) {
1431 Net::SSLeay::shutdown ($self->{tls});
1432
1433 &_dotls;
1434
1435 # we don't give a shit. no, we do, but we can't. no...
1436 # we, we... have to use openssl :/
1437 &_freetls;
1438 }
1439}
1440
1441sub _freetls {
1442 my ($self) = @_;
1443
1444 return unless $self->{tls};
1445
1305 Net::SSLeay::free (delete $self->{tls}) if $self->{tls}; 1446 Net::SSLeay::free (delete $self->{tls});
1306 1447
1307 delete $self->{_rbio}; 1448 delete @$self{qw(_rbio _wbio _tls_wbuf)};
1308 delete $self->{_wbio};
1309 delete $self->{_tls_wbuf};
1310 delete $self->{filter_r};
1311 delete $self->{filter_w};
1312} 1449}
1313 1450
1314sub DESTROY { 1451sub DESTROY {
1315 my $self = shift; 1452 my $self = shift;
1316 1453
1317 $self->stoptls; 1454 &_freetls;
1318 1455
1319 my $linger = exists $self->{linger} ? $self->{linger} : 3600; 1456 my $linger = exists $self->{linger} ? $self->{linger} : 3600;
1320 1457
1321 if ($linger && length $self->{wbuf}) { 1458 if ($linger && length $self->{wbuf}) {
1322 my $fh = delete $self->{fh}; 1459 my $fh = delete $self->{fh};
1337 @linger = (); 1474 @linger = ();
1338 }); 1475 });
1339 } 1476 }
1340} 1477}
1341 1478
1479=item $handle->destroy
1480
1481Shuts down the handle object as much as possible - this call ensures that
1482no further callbacks will be invoked and resources will be freed as much
1483as possible. You must not call any methods on the object afterwards.
1484
1485Normally, you can just "forget" any references to an AnyEvent::Handle
1486object and it will simply shut down. This works in fatal error and EOF
1487callbacks, as well as code outside. It does I<NOT> work in a read or write
1488callback, so when you want to destroy the AnyEvent::Handle object from
1489within such an callback. You I<MUST> call C<< ->destroy >> explicitly in
1490that case.
1491
1492The handle might still linger in the background and write out remaining
1493data, as specified by the C<linger> option, however.
1494
1495=cut
1496
1497sub destroy {
1498 my ($self) = @_;
1499
1500 $self->DESTROY;
1501 %$self = ();
1502}
1503
1342=item AnyEvent::Handle::TLS_CTX 1504=item AnyEvent::Handle::TLS_CTX
1343 1505
1344This function creates and returns the Net::SSLeay::CTX object used by 1506This function creates and returns the Net::SSLeay::CTX object used by
1345default for TLS mode. 1507default for TLS mode.
1346 1508
1374 } 1536 }
1375} 1537}
1376 1538
1377=back 1539=back
1378 1540
1541
1542=head1 NONFREQUENTLY ASKED QUESTIONS
1543
1544=over 4
1545
1546=item I C<undef> the AnyEvent::Handle reference inside my callback and
1547still get further invocations!
1548
1549That's because AnyEvent::Handle keeps a reference to itself when handling
1550read or write callbacks.
1551
1552It is only safe to "forget" the reference inside EOF or error callbacks,
1553from within all other callbacks, you need to explicitly call the C<<
1554->destroy >> method.
1555
1556=item I get different callback invocations in TLS mode/Why can't I pause
1557reading?
1558
1559Unlike, say, TCP, TLS connections do not consist of two independent
1560communication channels, one for each direction. Or put differently. The
1561read and write directions are not independent of each other: you cannot
1562write data unless you are also prepared to read, and vice versa.
1563
1564This can mean than, in TLS mode, you might get C<on_error> or C<on_eof>
1565callback invocations when you are not expecting any read data - the reason
1566is that AnyEvent::Handle always reads in TLS mode.
1567
1568During the connection, you have to make sure that you always have a
1569non-empty read-queue, or an C<on_read> watcher. At the end of the
1570connection (or when you no longer want to use it) you can call the
1571C<destroy> method.
1572
1573=item How do I read data until the other side closes the connection?
1574
1575If you just want to read your data into a perl scalar, the easiest way
1576to achieve this is by setting an C<on_read> callback that does nothing,
1577clearing the C<on_eof> callback and in the C<on_error> callback, the data
1578will be in C<$_[0]{rbuf}>:
1579
1580 $handle->on_read (sub { });
1581 $handle->on_eof (undef);
1582 $handle->on_error (sub {
1583 my $data = delete $_[0]{rbuf};
1584 undef $handle;
1585 });
1586
1587The reason to use C<on_error> is that TCP connections, due to latencies
1588and packets loss, might get closed quite violently with an error, when in
1589fact, all data has been received.
1590
1591It is usually better to use acknowledgements when transferring data,
1592to make sure the other side hasn't just died and you got the data
1593intact. This is also one reason why so many internet protocols have an
1594explicit QUIT command.
1595
1596=item I don't want to destroy the handle too early - how do I wait until
1597all data has been written?
1598
1599After writing your last bits of data, set the C<on_drain> callback
1600and destroy the handle in there - with the default setting of
1601C<low_water_mark> this will be called precisely when all data has been
1602written to the socket:
1603
1604 $handle->push_write (...);
1605 $handle->on_drain (sub {
1606 warn "all data submitted to the kernel\n";
1607 undef $handle;
1608 });
1609
1610=back
1611
1612
1379=head1 SUBCLASSING AnyEvent::Handle 1613=head1 SUBCLASSING AnyEvent::Handle
1380 1614
1381In many cases, you might want to subclass AnyEvent::Handle. 1615In many cases, you might want to subclass AnyEvent::Handle.
1382 1616
1383To make this easier, a given version of AnyEvent::Handle uses these 1617To make this easier, a given version of AnyEvent::Handle uses these
1386=over 4 1620=over 4
1387 1621
1388=item * all constructor arguments become object members. 1622=item * all constructor arguments become object members.
1389 1623
1390At least initially, when you pass a C<tls>-argument to the constructor it 1624At least initially, when you pass a C<tls>-argument to the constructor it
1391will end up in C<< $handle->{tls} >>. Those members might be changes or 1625will end up in C<< $handle->{tls} >>. Those members might be changed or
1392mutated later on (for example C<tls> will hold the TLS connection object). 1626mutated later on (for example C<tls> will hold the TLS connection object).
1393 1627
1394=item * other object member names are prefixed with an C<_>. 1628=item * other object member names are prefixed with an C<_>.
1395 1629
1396All object members not explicitly documented (internal use) are prefixed 1630All object members not explicitly documented (internal use) are prefixed

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